An extensive study of the spectral sensitivity of retinal ganglion cells in fish has been made to determine the character and complexity of spectral components driving the ganglion cell. Most ganglion cells of these retinas when isolated in very dim light show a lambda max of about 530 nm signifying a rod input. At higher levels of illumination the lambda max tends to shift to 650 nm although some cells show a lambda max of 500 nm. It is extremely rare to find in initial spectral at 450 nm. The response to illumination may be excitatory ("on" response) or inhibitory ("off" response), usually it is both. Center and surround antagonism is usual. The spectral sensitivity curves may be narrow or broad. Broad curves invariably can be shown to be composed of two or more spectral components each having the same sign (on or off) but different lambda max. Narrow curves occasionally show presence of more than one component and the additional component of opposite sign. As many as three spectrally different components can often be found in the same cell. The variety of patterns found suggests color moving in carp retinal ganglion cells is very complex.